This invention relates in general to chain scraper conveyors and in particular to a new and useful chain scraper conveyor construction having a catch or scraper assembly with a chain stirrup holder which is prestressed into a curved elastic deformation.
The invention relate particularly to a chain scraper conveyor, in conformity with the type, with conveying chute, central guided tension chain and catches attached thereto, which are guided in the chute side pieces. The catches have an underside with a chain link holder for an O-shaped chain link arranged parallel to the chute floor. The catches also have a chain stirrup holder, where a chain stirrup is placed on the chain link holder with the positioned chain link as well as in the chain stirrup holder, and the chain stirrup clamps the chain link, fixing into the chain link in the area of its center. The chain stirrup is provided with a set-screw on its stirrup ends which is set with play into a corresponding bore in the catch and is screwed in on the other side of the catch.
With the typical chain scraper conveyors known from the practice, the chain stirrup, in a static respect, is almost a rigid component, which undergoes, at most, a slight elastic deformation along the set-screws to the catch. The deformation does not cause any stretching of the chain stirrup, however, but only a clamping of the chain link. Considerable tolerances are adjusted between the chain stirrup and the chain stirrup holder, between the chain link and the chain link holder, and also especially along the chain stirrup, in order to ensure that the chain stirrup always fits in the chain stirrup holder. The fastening arrangement, as a whole, can also hold chain links, which for their part bring along considerable tolerances required by production or operation. The chain stirrup holds the chain link fast with clamping forces which work in the direction of the set-screws. In operational use, especially in the area of the so-called roller turns, stresses occur which cause considerable moments between the catches and the tension chain subjected to a propelling force. These stresses lead, along with screwing with a high screw-moment, to tolerance limited relative motions between the described parts and to the disorientation of the catch with respect to the chain. The holders and the chain link held fast under the chain stirrup incline to one side, and an uncontrolled play disrupting the operation may appear. As a consequence, the useful lifetime of the scraper conveyor is impaired by these effects.